how to import the sample data to joomla 1.5 website
Open the directory installation->sql->mysql find the sample file data sample_data.sql.Open the file data sample_data.sql in your editor and edit the database table prefix. Use the Find and Replace command of your editor and enter #__ (hash double-underscore) in the Find field and jos_ in the Replace field and select Enter. Save the file ensuring this is done with UTF-8 NO BOM encoding only.
If you require the sample data to be installed to the database you must complete a further Import process. Select the Import tab in the PHPMyAdmin interface and browse to the renamed installation directory and select the sample_data.sql file
Once the file is selected from the browser click Go.
If all goes according to plan you will receive a confirmation message.
"Import has been successfully finished,210 queries executed"